Rasmus Lerdorf has shared a post to his site detailing how he upgraded his EdgeRouter Lite router (hardware) to use PHP 7 for the uI handling and processing, upgrading it from the PHP 5.4 it came installed with.

After nearly 7 years of service I retired my Asus RT-16 router, which wasn't really a router, but a re-purposed wifi access point running AdvancedTomato. In its place I got a Ubiquiti EdgeRouter Lite. It is Debian-based and has a dual-core 500MHz 64-Bit MIPS CPU (Cavium Octeon+), 512M of ram and a 4G removable onboard USB stick for < $100. The router is completely open and, in fact, any advanced configuration has to be done from the command line. The Web UI has been improving, but there are still many things you can't do in it. In other words, exactly the type of device I prefer.

He made use of the open platform the router has to upgrade both the PHP installation and a bit of the web UI code to make things work happily with PHP 7. There's just three steps in his process:

Getting a Big-Endian MIPS64 build of PHP 7

Configuration (php.ini)

Fixing broken stuff

The "broken stuff" in this last item was only a few small changes that needed to be made to the web UI code for raw POST data fetching and session writes. He ends the post with a little summary of the performance post-changes and some about the opcode handling and memory use per request.